<html>
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>JavaScript</title>
</head>
<body>
</body>
<script type="text/javascript">
    document.write("使用JavaScript脚本语言循环输出hello world!")
    for(var i = 0; i < 3; i++){
        document.write("<h1>hello world!</h1>");
    }
</script>
</html>